This invention relates to a heat exchanger structure for a plurality of electrochemical storage cells, with at least one duct component through which thermal control medium flows.
German patent specification DE 198 49 491 C1 discloses a device for the thermal control of a plurality of electrochemical storage cells, in which heat exchanger ducts are arranged between a plurality of layers of parallelepipedic storage cells. The heat exchanger ducts issue into distributors and are connected to the distributors to form a rigid grid-like frame. The heat exchanger ducts are designed as tubular elements of rectangular cross section and support the storage cells. To fix the storage cells, spacers are provided, which, within a layer of storage cells, retain these at a predetermined distance from one another. Furthermore, German publication DE 90 02 249 U1 and European publication EP 0 917 230 A1 each disclose a heat exchanger structure for a plurality of electrochemical storage cells, with at least one duct component through which thermal control media flow. The duct component of the heat exchanger structure disclosed from EP 0 917 230 A1 has shaped portions adapted to the storage cells.
One object of this invention is to provide a heat exchanger structure for a plurality of electrochemical storage cells, which, along with a simple construction, allows a good thermal control of the individual storage cells.
For this purpose, according to the invention, a heat exchanger structure having the features claimed is provided. By a heat exchanger duct being formed between two parallel material strips which have shaped portions adapted to the storage cells, the storage cells are held by the duct component with a form fit. There is therefore no need for any additional spacer or holding elements in order to secure the storage cells against slipping out of place. By the material strips engaging on the storage cells with a form fit, a large contact surface and consequently a good thermal control of the storage cells are obtained. The shaped portions, adapted to the storage cells, of the material strips may in this case be produced simply by the bending of the material strips or even during the manufacturing process.
Advantageous developments of the invention are specified in the dependent claims.
Since the duct component has supporting members arranged at adjacent longitudinal edges of the material strips and each having a spacer web extending between the material strips, a particularly simple construction of the duct component from only four components, to be precise two material strips and two supporting members, is obtained. With the aid of the spacer web extending between the material strips, the distance between the material strips arranged parallel to one another and consequently the cross section of the heat exchanger duct are defined. A particularly simple mounting of the duct component is obtained when the supporting member has a fixing web which extends perpendicularly to the spacer web and which is adapted to the shaped portions of the material strips. The supporting member therefore merely has to be introduced between the material strips, until the longitudinal edges of the material strips butt against the fixing web. The supporting member may in this case be produced in one piece with the spacer web and with the fixing web, this being conducive to the simple construction of the heat exchanger structure.
A constant cross section of the heat exchanger duct can be ensured in a simple way by providing a spacer strip extending in the longitudinal direction of the material strips between the two material strips of the duct component in their middle region. In this way, for example, two heat exchanger ducts can also be produced in one duct component. The heat exchanger structure is suitable in a particular way for being arranged between two layers of storage cells when the duct component has two heat exchanger ducts between two material strips in each case, one heat exchanger duct lying on a top side and the other heat exchanger duct on an underside of the duct component. The cooling ducts may in this case be symmetrical to one another, as a result of which, along with a simple construction, a forward flow and the return flow of the thermal control medium between two layers of storage cells can be implemented. A contribution to a simple construction is made by the fact that two one-piece supporting members are provided, which connect the four material strips of the two heat exchanger ducts at their adjacent longitudinal edges in each case. Even when two heat exchanger ducts are provided for each duct component, the latter can be assembled in a simple way from four material strips and two supporting members.
One design of the heat exchanger structure is advantageous in that two duct components for receiving at least one storage cell are arranged opposite one another and in such a way that shaped portions extending in contra-directional directions are located opposite one another. This ensures not only a secure hold of a storage cell in the contra-directed shaped portions located opposite one another, but also the good thermal control, for example cooling, of the said storage cell due to a large contact surface between the heat exchanger ducts and the storage cell. Such a design also makes it possible to have a particularly space-saving arrangement of the storage cells in a plurality of layers, the individual layers of storage cells being capable of being offset to one another with the effect of a particularly compact arrangement.
When a plurality of duct components are arranged essentially in one plane and parallel to one another, adjacent end faces of the duct components being connected to a distributor, a planar module is obtained, which can be arranged between two layers of storage cells for the thermal control and fixing in position of the latter. The heat exchanger ducts are connected to distributor ducts in the distributors, and, when two heat exchanger ducts through which the flow passes contra-directionally are provided for each duct component, two distributors are likewise provided in the distributor component.
A particularly expedient modular configuration is obtained by the provision of at least two distributors which are connected by means of at least one fixing element running parallel to the duct components. A stable and flat module is thereby provided, in which the distributors in the storage cells are secured additionally by the fixing element. When three fixing elements are provided for each module, this results in a stable frame consisting of the distributors and of the fixing elements arranged at the ends and in the middle of the distributors. The duct components can consequently be of particularly lightweight design, since the frame is formed from the distributors and the fixing elements and the duct components therefore no longer have to assume a supporting function. The fixing element in this case also serves for securing the storage cells in the longitudinal and transverse directions of the frame. A plurality of such modules may be arranged one above the other in layers, in order, together with the storage cells, to form a stable composite structure.
For the thermal control of cylindrical storage cells, what are known as round cells, there is provision for the shaped portions of the material strips to have the form of cylinder segments. When, as seen in the longitudinal direction, the material strips have shaped portions with alternately contra-directional curvatures, a wavy shape of the material strips is obtained. When layers of storage cells are arranged in each case so as to be offset by the amount of half the wavelength of the wavy shape, a very high packing density of the storage cells, at the same time with good thermal control and good fixing in position of the storage cells, can be achieved. Particularly good thermal control of the storage cells by means of a large contact surface of the heat exchanger ducts with the storage cells is obtained when, as seen in the longitudinal direction, the material strips have shaped portions with co-directional curvatures. Such a design is particularly suitable for a non-offset arrangement of the individual layers of the storage cells in relation to one another.
The object mentioned above can also be achieved by means of an electrochemical energy store as claimed. In such an energy store, the storage cells are arranged in a plurality of parallel layers, thus resulting in a simple and compact construction of the energy store, along with a secure fixing and good thermal control of the storage cells.
A particularly compact construction of the energy store can be achieved when the thermal control medium between a first and a second layer of storage cells flows contra-directionally to the thermal control medium between the second and a third layer of storage cells. In such an arrangement, only one layer of heat exchanger ducts is necessary between two layers of storage cells, so that a flat construction of the energy store is obtained.
A particularly uniform thermal control of the storage cells of the energy store is obtained when the thermal control medium flows into two contra-directional directions between two layers of storage cells in heat exchanger ducts separated from one another. By virtue of the contra-flow of the thermal control medium between two layers, an insufficient cooling or thermal control of storage cells lying far downstream is avoided.
Further features and advantages of the invention are specified in the following description, with reference to the accompanying drawings.